Illumination optical system, exposure apparatus and device manufacturing method

ABSTRACT

The illumination optical system for illuminating an illumination target surface with light from a light source is provided with a polarization converting member which converts a polarization state of incident light to form a pupil intensity distribution in a predetermined polarization state on an illumination pupil of the illumination optical system; and a phase modulating member which is arranged in the optical path on the illumination target surface side with respect to the polarization converting member and which transmits light from the pupil intensity distribution so as to convert linearly polarized light thereof polarized in a first direction, into required elliptically polarized light and maintain a polarization state of linearly polarized light polarized in a second direction (X-direction or Y-direction) obliquely intersecting with the first direction, in order to reduce influence of retardation caused by a subsequent optical system between the polarization converting member and the illumination target surface.

This is a Continuation Application of application Ser. No. 15/390,127,filed Dec. 23, 2016, which is a Continuation Application of applicationSer. No. 14/563,275 filed Dec. 8, 2014, which in turn is a DivisionalApplication of application Ser. No. 13/161,877 filed Jun. 16, 2011. Thedisclosure of the prior application is hereby incorporate by referenceherein in its entirety.

BACKGROUND 1. Field

An embodiment of the invention relates to an illumination opticalsystem, an exposure apparatus, and a device manufacturing method. Moreparticularly, the embodiment relates to an illumination optical systemsuitably applicable to an exposure apparatus for manufacturing devices,for example, such as semiconductor devices, imaging devices, liquidcrystal display devices, and thin film magnetic heads by the lithographyprocess.

2. Description of the Related Art

In the typical exposure apparatus of this type, light emitted from alight source travels through a fly's eye lens as an optical integratorto form a secondary light source as a substantial surface illuminantconsisting of a large number of light sources (generally, apredetermined light intensity distribution on an illumination pupil).The light intensity distribution on the illumination pupil will bereferred to hereinafter as “pupil intensity distribution.” Theillumination pupil is defined as a position where an illumination targetsurface becomes a Fourier transform plane of the illumination pupil byaction of an optical system between the illumination pupil and theillumination target surface (a mask or a wafer in the case of theexposure apparatus).

Light from the secondary light source is condensed by a condenseroptical system and thereafter illuminates the mask with a predeterminedpattern thereon in a superimposed manner. Light passing through the masktravels through a projection optical system to be focused on the wafer,whereby the mask pattern is projected and exposed (or transferred) ontothe wafer. The pattern formed on the mask is highly microscopic and, inorder to accurately transfer this microscopic pattern onto the wafer, itis essential to obtain a uniform illuminance distribution on the wafer.

In recent years, for realizing an illumination condition suitable forfaithful transfer of the microscopic pattern in any direction, there isthe proposed technology of forming the annular secondary light source(annular pupil intensity distribution) on the illumination pupil at ornear the rear focal plane of the fly's eye lens and setting the beampassing through the annular secondary light source, in a linearlypolarized state having the direction of polarization along acircumferential direction thereof (hereinafter referred to simply as“circumferentially polarized state”) (e.g., cf. InternationalPublication WO2005/076045)

SUMMARY

According to an embodiment, an illumination optical system forilluminating an illumination target surface with light from a lightsource, comprising:

a polarization converting member which can be arranged in an opticalpath of the illumination optical system and which converts apolarization state of incident light so as to form a pupil intensitydistribution in a predetermined polarization state on an illuminationpupil of the illumination optical system; and

a phase modulating member which can be arranged in the optical path ofthe illumination optical system and which transmits light from the pupilintensity distribution so as to convert linearly polarized light thereofpolarized in a first direction, into required elliptically polarizedlight and maintain a polarization state of linearly polarized lightthereof polarized in a second direction obliquely intersecting with thefirst direction, in order to reduce influence of retardation caused by asubsequent optical system between the polarization converting member andthe illumination target surface.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

A general architecture that implements the various features of theinvention will now be described with reference to the drawings. Thedrawings and the associated descriptions are provided to illustrateembodiments of the invention and not to limit the scope of theinvention.

FIG. 1 is an exemplary drawing schematically showing a configuration ofan exposure apparatus according to an embodiment of the presentinvention;

FIG. 2 is an exemplary drawing showing a state in which an annular lightintensity distribution is formed on a pupil plane of an afocal lens;

FIG. 3 is an exemplary drawing schematically showing a configuration ofa polarization converting member according to the embodiment of thepresent invention;

FIG. 4 is an exemplary drawing for explaining the optical rotatory powerof rock crystal;

FIG. 5 is an exemplary drawing showing an annular light intensitydistribution in an almost continuous, circumferentially polarized stateformed on an illumination pupil just behind the polarization convertingmember;

FIG. 6 is an exemplary drawing for explaining the problem of theconventional technology about the light intensity distribution of FIG.5;

FIG. 7 is an exemplary drawing schematically showing a configuration ofa phase modulating member according to the embodiment;

FIG. 8 is an exemplary drawing for explaining the action of the phasemodulating member in the embodiment;

FIG. 9 is an exemplary drawing showing an annular light intensitydistribution in an almost continuous, radially polarized state formed onthe illumination pupil just behind the polarization converting member;

FIG. 10 is an exemplary drawing for explaining the problem of theconventional technology about the light intensity distribution of FIG.9;

FIG. 11 is an exemplary drawing showing an octupolar light intensitydistribution in a circumferentially polarized state formed on theillumination pupil just behind the polarization converting member;

FIG. 12 is an exemplary drawing showing an octupolar light intensitydistribution in a radially polarized state formed on the illuminationpupil just behind the polarization converting member;

FIG. 13 is an exemplary drawing showing an X-shaped quadrupolar lightintensity distribution in a circumferentially polarized state formed onthe illumination pupil just behind the polarization converting member;

FIG. 14 is an exemplary drawing showing an X-shaped quadrupolar lightintensity distribution in a radially polarized state formed on theillumination pupil just behind the polarization converting member;

FIG. 15 is an exemplary flowchart showing manufacturing blocks ofsemiconductor devices; and

FIG. 16 is an exemplary flowchart showing manufacturing blocks of aliquid crystal device such as a liquid crystal display device.

DETAILED DESCRIPTION

Various embodiments will be described on the basis of the accompanyingdrawings. FIG. 1 is an exemplary drawing schematically showing aconfiguration of an exposure apparatus according to an embodiment of thepresent invention. In FIG. 1, the Z-axis is set along a direction of anormal to an exposure surface (transfer surface) of a wafer W being aphotosensitive substrate, the Y-axis along a direction parallel to theplane of FIG. 1 in the exposure surface of the wafer W, and the X-axisalong a direction perpendicular to the plane of FIG. 1 in the exposuresurface of the wafer W.

With reference to FIG. 1, exposure light (illumination light) issupplied from a light source LS in the exposure apparatus of the presentembodiment. The light source LS applicable herein can be, for example,an ArF excimer laser light source to supply light at the wavelength of193 nm or a KrF excimer laser light source to supply light at thewavelength of 248 nm. A beam emitted from the light source LS travelsvia a shaping optical system 1, a polarization state switching unit 2,and a diffraction optical element 3 to enter an afocal lens 4. Theshaping optical system 1 has a function to convert the nearly parallelbeam from the light source LS into a beam having a predeterminedrectangular cross section and to guide the resultant beam to thepolarization state switching unit 2.

The polarization state switching unit 2 is provided with, in order fromthe light source side, a quarter wave plate 2 a which is configured withits crystal optic axis being rotatable around the optical axis AX andwhich converts elliptically polarized light incident thereinto, intolinearly polarized light, a half wave plate 2 b which is configured withits crystal optic axis being rotatable around the optical axis AX andwhich changes a direction of polarization of linearly polarized lightincident thereinto, and a depolarizer (depolarizing element) 2 c whichcan be inserted into or retracted from an illumination optical path. Thepolarization state switching unit 2 functions as follows: in a state inwhich the depolarizer 2 c is retracted from the illumination opticalpath, the polarization state switching unit 2 converts the light fromthe light source LS into linearly polarized light having a desiredpolarization direction and injects the resultant light into thediffraction optical element 3; in a state in which the depolarizer 2 cis set in the illumination optical path, the polarization stateswitching unit 2 converts the light from the light source LS intosubstantially unpolarized light and injects the unpolarized light intothe diffraction optical element 3.

The afocal lens 4 is an afocal system (afocal optic) which is so setthat its front focal position approximately coincides with the positionof the diffraction optical element 3 and that its rear focal positionapproximately coincides with a position of a predetermined plane IPindicated by a dashed line in the drawing. The diffraction opticalelement 3 is constructed by forming blocks having the pitch nearly equalto the wavelength of the exposure light (illumination light), in asubstrate, and has an action to diffract an incident beam at desiredangles. It is assumed hereinafter for easier description that thediffraction optical element 3 is one for annular illumination.

The diffraction optical element 3 for annular illumination functions insuch a manner that when a parallel beam with a rectangular cross sectionis incident thereinto, it forms an annular light intensity distributionin the far field (or Fraunhofer diffraction region). Therefore, thenearly parallel beam incident into the diffraction optical element 3forms an annular light intensity distribution 21 on a pupil plane of theafocal lens 4, as shown in FIG. 2, and is then emitted in an annularangle distribution from the afocal lens 4. There are a polarizationconverting member 5A, a phase modulating member 5B, and a conical axiconsystem 6 arranged at or near the pupil position of the afocal lens 4 inthe optical path between front lens unit 4 a and rear lens unit 4 b ofthe afocal lens 4. The configurations and actions of the polarizationconverting member 5A, phase modulating member 5B, and conical axiconsystem 6 will be described later.

The light passing through the afocal lens 4 travels through a zoom lens7 for varying the σ value (σ value=mask-side numerical aperture of theillumination optical system/mask-side numerical aperture of theprojection optical system), to enter a micro fly's eye lens (or fly'seye lens) 8 as an optical integrator. The micro fly's eye lens 8 is, forexample, an optical element consisting of a large number of microscopiclenses with a positive refracting power arranged lengthwise andcrosswise and densely, and is constructed by forming the microscopiclens group in a plane-parallel plate by etching.

Each microscopic lens forming the micro fly's eye lens is smaller thaneach lens element forming the fly's eye lens. In the micro fly's eyelens, different from the fly's eye lens consisting of lens elementsisolated from each other, the large number of microscopic lenses(microscopic refracting faces) are integrally formed without beingisolated from each other. However, the micro fly's eye lens is anoptical integrator of the same wavefront division type as the fly's eyelens in that the lens elements with the positive refracting power arearranged lengthwise and crosswise. It is also possible to use, forexample, a cylindrical micro fly's eye lens as the micro fly's eye lens8. The configuration and action of the cylindrical micro fly's eye lensare disclosed, for example, in U.S. Pat. No. 6,913,373.

The position of the predetermined plane IP is arranged at or near thefront focal position of the zoom lens 7 and an entrance surface of themicro fly's eye lens 8 is arranged at or near the rear focal position ofthe zoom lens 7. In other words, the zoom lens 7 arranges thepredetermined plane IP and the entrance surface of the micro fly's eyelens 8 substantially in a Fourier transform relation and, in turn,arranges the pupil plane of the afocal lens 4 and the entrance surfaceof the micro fly's eye lens 8 substantially optically conjugate witheach other.

Therefore, for example, an annular illumination field centered on theoptical axis AX is formed on the entrance surface of the micro fly's eyelens 8 as on the pupil plane of the afocal lens 4. The overall shape ofthis annular illumination field varies in a similarity relationdepending upon the focal length of the zoom lens 7. The beam incidentinto the micro fly's eye lens 8 is divided two-dimensionally to form asecondary light source with a light intensity distribution substantiallyidentical to the illumination field formed on the entrance surface ofthe micro fly's eye lens 8, i.e., a secondary light source (pupilintensity distribution) consisting of a substantial surface illuminantof an annular shape centered on the optical axis AX, at a rear focalplane of the micro fly's eye lens 8 or at a position near it.

An illumination aperture stop 9 having an annular aperture (lighttransmitting portion) corresponding to the annular secondary lightsource is arranged, if necessary, at or near the rear focal plane of themicro fly's eye lens 8. The illumination aperture stop 9 is configuredso as to be freely inserted into or retracted from the illuminationoptical path and so as to be interchangeable with a plurality ofaperture stops having apertures of different sizes and shapes. Anaperture stop switching method applicable herein can be, for example,the well-known turret method or slide method. The illumination aperturestop 9 is arranged at a position substantially optically conjugate withan entrance pupil plane of projection optical system PL and defines arange of contribution of the secondary light source to illumination.

The light having traveled through the micro fly's eye lens 8 and theillumination aperture stop 9 travels through a condenser optical system10 to illuminate a mask blind 11 in a superimposed manner. In this way,a rectangular illumination field according to the shape and focal lengthof the microscopic lenses of the micro fly's eye lens 8 is formed on themask blind 11 as an illumination field stop. The light having traveledthrough a rectangular aperture (light transmitting portion) of the maskblind 11 travels via an imaging optical system 12 consisting of a frontlens unit 12 a and a rear lens unit 12 b, to illuminate a mask M onwhich a predetermined pattern is formed, in a superimposed manner.

Namely, the imaging optical system 12 forms an image of the rectangularaperture of the mask blind 11 on the mask M. A pupil of the imagingoptical system 12 is another illumination pupil located at a positionoptically conjugate with the illumination pupil at or near the rearfocal plane of the micro fly's eye lens 8. Therefore, an annular pupilintensity distribution is also formed at the position of the pupil ofthe imaging optical system 12 as at the illumination pupil just behindthe micro fly's eye lens 8.

The pattern to be transferred is formed on the mask M held on a maskstage MS. The light passing through the pattern of the mask M travelsthrough the projection optical system PL to form an image of the maskpattern on the wafer (photosensitive substrate) W held on a wafer stageWS. In this way, the pattern of the mask M is sequentially exposed ineach exposure region on the wafer W by full-shot exposure or by scanexposure with two-dimensional drive and control of the wafer W in aplane (XY plane) perpendicular to the optical axis AX of the projectionoptical system PL. In performing the scan exposure, the mask stage MSand the wafer stage WS are driven at a speed ratio according to amagnification of the projection optical system PL, for example, alongthe Y-direction.

The conical axicon system 6 is composed of, in order from the lightsource side, a first prism member 6 a with a plane on the light sourceside and a refracting surface of a concave conical shape on the maskside, and a second prism member 6 b with a plane on the mask side and arefracting surface of a convex conical shape on the light source side.The refracting surface of the concave conical shape of the first prismmember 6 a and the refracting surface of the convex conical shape of thesecond prism member 6 b are formed in such a complementary relation asto be able to abut each other. At least one of the first prism member 6a and the second prism member 6 b is configured to be movable along theoptical axis AX so that the spacing between the first prism member 6 aand the second prism member 6 b can vary.

In a state in which the first prism member 6 a and the second prismmember 6 b abut each other, the conical axicon system 6 functions as aplane-parallel plate to cause no effect on the annular secondary lightsource formed. However, as the first prism member 6 a and the secondprism member 6 b are separated away from each other, the outsidediameter (inside diameter) of the annular secondary light source varieswhile the width of the annular secondary light source (half of thedifference between the outside diameter and the inside diameter of theannular secondary light source) is kept constant. Namely, the annularratio (inside diameter/outside diameter) and the size of the annularsecondary light source (outside diameter) vary.

The zoom lens 7 functions to enlarge or reduce the overall shape of theannular secondary light source in a similarity relation. For example,when the focal length of the zoom lens 7 is increased from a minimum toa predetermined value, the overall shape of the annular secondary lightsource is increased in a similarity relation. In other words, the widthand size (outside diameter) of the secondary light source both varywithout change in the annular ratio of the annular secondary lightsource, by the action of the zoom lens 7. In this manner, the annularratio and size (outside diameter) of the annular secondary light sourcecan be controlled by the actions of the conical axicon system 6 and thezoom lens 7.

In the present embodiment, as described above, the mask M arranged onthe illumination target surface of the illumination optical system(1-12) is illuminated by Köhler illumination using the secondary lightsource formed by the micro fly's eye lens 8, as a light source. For thisreason, the position where the secondary light source is formed isoptically conjugate with the position of the aperture stop AS of theprojection optical system PL and the plane where the secondary lightsource is formed can be called an illumination pupil plane of theillumination optical system (1-12). Typically, the illumination targetsurface (the surface where the mask M is arranged, or the surface wherethe wafer W is arranged if the illumination optical system is consideredto include the projection optical system PL) is an optical Fouriertransform plane with respect to the illumination pupil plane.

A pupil intensity distribution is a light intensity distribution(luminance distribution) on the illumination pupil plane of theillumination optical system (1-12) or on a plane optically conjugatewith the illumination pupil plane. When the number of wavefrontdivisions by the micro fly's eye lens 8 is relatively large, the globallight intensity distribution formed on the entrance plane of the microfly's eye lens 8 demonstrates a high correlation with the global lightintensity distribution (pupil intensity distribution) of the entiresecondary light source. For this reason, the light intensitydistributions on the entrance plane of the micro fly's eye lens 8 and ona plane optically conjugate with the entrance place (e.g., the pupilplane of the afocal lens 4) can also be called pupil intensitydistributions. Namely, the pupil of the afocal lens 4 which is a planeoptically conjugate with the entrance plane of the micro fly's eye lens8 can also be called an illumination pupil.

If a diffraction optical element for multi-polar illumination (dipolarillumination, quadrupolar illumination, octupolar illumination, or thelike) (not shown) is set instead of the diffraction optical element 3for annular illumination in the illumination optical path, multi-polarillumination can be implemented. The diffraction optical element formulti-polar illumination functions in such a manner that when a parallelbeam with a rectangular cross section is incident thereinto, it forms alight intensity distribution of a multi-polar shape (dipolar,quadrupolar, octupolar, or other shape) in the far field. Therefore,beams having traveled via the diffraction optical element formulti-polar illumination form an illumination field of a multi-polarshape, for example, consisting of a plurality of illumination zones of apredetermined shape (arcuate, circular, or other shape) centered on theoptical axis AX on the entrance plane of the micro fly's eye lens 8. Asa result, the secondary light source of the same multi-polar shape asthe illumination field formed on the entrance plane of the micro fly'seye lens 8 is also formed at or near the rear focal plane of the microfly's eye lens 8.

If a diffraction optical element for circular illumination (not shown)is set instead of the diffraction optical element 3 for annularillumination in the illumination optical path, ordinary circularillumination can be implemented. The diffraction optical element forcircular illumination functions in such a manner that when a parallelbeam with a rectangular cross section is incident thereinto, it forms alight intensity distribution of a circular shape in the far field.Therefore, a beam having traveled via the diffraction optical elementfor circular illumination forms, for example, an illumination field of acircular shape centered on the optical axis AX on the entrance plane ofthe micro fly's eye lens 8. As a result, the secondary light source ofthe same circular shape as the illumination field formed on the entranceplane is also formed at or near the rear focal plane of the micro fly'seye lens 8. If a diffraction optical element with an appropriateproperty (not shown) is set instead of the diffraction optical element 3for annular illumination in the illumination optical path, modifiedillumination of any one of various forms can be implemented. A switchingmethod of the diffraction optical element 3 applicable herein can be,for example, the well-known turret method or slide method.

Instead of the above-described diffraction optical element 3 or inaddition to the diffraction optical element 3, it is also possible toapply, for example, a spatial light modulator in which orientations of aplurality of mirror elements arranged two-dimensionally are variedcontinuously or discretely each in a plurality of stages. The spatiallight modulator of this type applicable herein can be, for example, oneof the spatial light modulators disclosed in European Patent ApplicationLaid-Open No. 779530, U.S. Pat. Nos. 6,900,915, 7,095,546, and JapanesePatent Application Laid-Open No. 2006-113437. The illumination opticalsystem using such an active spatial light modulator is disclosed, forexample, in U.S. Patent Application Laid-Open No. 2009/0073411, U.S.Patent Application Laid-Open No. 2009/0091730, U.S. Patent ApplicationLaid-Open No. 2009/0109417, U.S. Patent Application Laid-Open No.2009/0128886, U.S. Patent Application Laid-Open No. 2009/0097094, U.S.Patent Application Laid-Open No. 2009/0097007, U.S. Patent ApplicationLaid-Open No. 2009/0185154, and U.S. Patent Application Laid-Open No.2009/0116093. The disclosures of above European Patent ApplicationLaid-Open No. 779530, U.S. Pat. Nos. 6,900,915, 7,095,546, JapanesePatent Application Laid-Open No. 2006-113437, U.S. Patent ApplicationLaid-Open No. 2009/0073411, U.S. Patent Application Laid-Open No.2009/0091730, U.S. Patent Application Laid-Open No. 2009/0109417, U.S.Patent Application Laid-Open No. 2009/0128886, U.S. Patent ApplicationLaid-Open No. 2009/0097094, U.S. Patent Application Laid-Open No.2009/0097007, U.S. Patent Application Laid-Open No. 2009/0185154, andU.S. Patent Application Laid-Open No. 2009/0116093 are incorporatedherein by reference.

FIG. 3 is an exemplary drawing schematically showing the configurationof the polarization converting member. The polarization convertingmember 5A is arranged at or near the pupil position of the afocal lens4, i.e., at or near the position of the illumination pupil of theillumination optical system (1-12), as described above. It is assumedhereinafter for easier understanding of description that thepolarization converting member 5A is arranged at a position just infront of the illumination pupil in the optical path of the afocal lens4. When the diffraction optical element 3 for annular illumination isarranged in the illumination optical path, a beam having an annularcross section is incident into the polarization converting member 5A.

The polarization converting member 5A has a form of a plane-parallelplate in whole and is made of a crystal material being an opticalmaterial having an optical rotatory power, e.g., rock crystal. In astate in which the polarization converting member 5A is positioned inthe optical path, an entrance surface thereof (and, therefore, an exitsurface) is perpendicular to the optical axis AX and the crystal opticaxis thereof is coincident with the direction of the optical axis AX(i.e., coincident with the Z-direction being the traveling direction ofincident light). The polarization converting member 5A has a contour ofa circular shape (or a circular ring shape which is not shown) centeredon the optical axis AX, as shown in FIG. 3, and has eight dividedregions resulting from equal division of the circular contour into eightequal segments along the circumferential direction of the circle.

Specifically, the polarization converting member 5A has, as the eightdivided regions, regions 51 a, 51 b, 51 c, 51 d, 51 e, 51 f, 51 g, and51 h. The divided regions 51 a-51 h are regions that are separated sothat eight arcuate beams obtained by equal division of the incidentannular beam (indicated by two dashed circles in FIG. 3) into eightequal parts along the circumferential direction, pass through therespective regions. Among the divided regions 51 a-51 h, any two dividedregions adjacent in the circumferential direction have respectivethicknesses (lengths along the direction of the optical axis AX)different from each other and any two divided regions opposed to eachother on both sides of the optical axis AX have respective thicknessesidentical with each other.

The polarization converting member 5A is a single member formedintegrally by an etching process of one surface (entrance surface orexit surface) of a plane-parallel plate of rock crystal. Namely, onesurface of the polarization converting member 5A is formed in an unevenshape with eight linear blocks extending radially from the centerthereof, and the other surface is formed in a planar shape.Alternatively, the polarization converting member 5A is composed of acombination of eight optical rotatory members corresponding to thedivided regions 51 a-51 h.

The optical rotatory power of rock crystal will be briefly describedbelow with reference to FIG. 4. With reference to FIG. 4, an opticalmember 100 of a plane-parallel plate shape made of rock crystal and inthickness d is arranged so that its crystal optic axis coincides withthe optical axis AX. In this case, owing to the optical rotatory powerof the optical member 100, the direction of polarization of linearlypolarized light incident thereinto is rotated by θ around the opticalaxis AX and the linearly polarized light thus rotated is emitted.

At this time, the rotation angle (optical rotatory angle) θ of thepolarization direction owing to the optical rotatory power of theoptical member 100 is represented by formula (a) below using thethickness d of the optical member 100 and the optical rotatory power ρof rock crystal. In general, the optical rotatory power ρ of rockcrystal has wavelength dependence (a property of optical rotatory powervarying depending upon the wavelength of light used: optical rotatorydispersion) and, specifically, tends to increase with decrease of thewavelength of the used light. According to the description in TadaoTsuruta, “Ouyou Kogaku (Applied Optics) II,” p 167, BAIFUKAN CO., LTD.(1990), the optical rotatory power ρ of rock crystal is 153.9°/mm forlight with the wavelength of 250.3 nm.

θ=d·ρ  (a)

Referring again to FIG. 3, the divided region 51 a of the polarizationconverting member 5A is arranged so that its center line (straight lineextending radially from the optical axis AX) coincides with a straightline extending in the −Y-direction through the optical axis AX. Thedivided region 51 a has the thickness set so that when Y-directionallylinearly polarized light having the polarization direction along theY-direction is incident thereinto, it emits linearly polarized lighthaving the polarization direction along a direction resulting from +90°(90° counterclockwise in FIG. 3) rotation of the Y-direction. Thedivided region 51 b adjacent to the divided region 51 a along thecounterclockwise circumferential direction in FIG. 3 has the thicknessset so that when Y-directionally linearly polarized light is incidentthereinto, it emits linearly polarized light having the polarizationdirection along a direction resulting from +135° rotation of theY-direction.

The divided region 51 c adjacent to the divided region 51 b has thethickness set so that when Y-directionally linearly polarized light isincident thereinto, it emits linearly polarized light having thepolarization direction along a direction resulting from +180° rotationof the Y-direction. The divided region 51 d adjacent to the dividedregion 51 c has the thickness set so that when Y-directionally linearlypolarized light is incident thereinto, it emits linearly polarized lighthaving the polarization direction along a direction resulting from +225°rotation of the Y-direction. The divided region 51 e adjacent to thedivided region 51 d and opposed to the divided region 51 a with theoptical axis AX in between has the thickness set so that whenY-directionally linearly polarized light is incident thereinto, it emitslinearly polarized light having the polarization direction along adirection resulting from +90° rotation of the Y-direction, as thedivided region 51 a does.

The divided region 51 f opposed to the divided region 51 b has thethickness set so that when Y-directionally linearly polarized light isincident thereinto, it emits linearly polarized light having thepolarization direction along a direction resulting from +135° rotationof the Y-direction. The divided region 51 g opposed to the dividedregion 51 c has the thickness set so that when Y-directionally linearlypolarized light is incident thereinto, it emits linearly polarized lighthaving the polarization direction along a direction resulting from +180°rotation of the Y-direction. The divided region 51 h opposed to thedivided region 51 d has the thickness set so that when Y-directionallylinearly polarized light is incident thereinto, it emits linearlypolarized light having the polarization direction along a directionresulting from +225° rotation of the Y-direction.

The action of the polarization converting member 5A will be described onthe assumption that Y-directionally linearly polarized light is incidentinto the polarization converting member 5A, with reference to FIG. 5. Anarcuate beam F1 incident into the divided region 51 a of thepolarization converting member 5A turns into X-directionally linearlypolarized light (laterally polarized light) having the polarizationdirection along the direction resulting from +90° (90° counterclockwisein FIG. 5) rotation of the Y-direction, i.e., along the X-direction. Abeam F2 generated through the divided region 51 b turns into obliquelylinearly polarized light (obliquely polarized light) having thepolarization direction along the oblique direction resulting from +135°rotation of the Y-direction.

A beam F3 generated through the divided region 51 c turns intoY-directionally linearly polarized light (vertically polarized light)having the polarization direction along the direction resulting from+180° rotation of the Y-direction, i.e., along the Y-direction.Similarly, a beam F4 generated through the divided region 51 d turnsinto obliquely linearly polarized light having the polarizationdirection along the oblique direction resulting from +225° rotation ofthe Y-direction. A beam F5 generated through the divided region 51 eturns into X-directionally linearly polarized light as the beam F1opposed thereto with the optical axis AX in between does.

A beam F6 generated through the divided region 51 f turns into obliquelylinearly polarized light having the polarization direction along theoblique direction resulting from +135° rotation of the Y-direction, asthe beam F2 opposed thereto with the optical axis AX in between does. Abeam F7 generated through the divided region 51 g turns intoY-directionally linearly polarized light as the beam F3 opposed theretowith the optical axis AX in between does. A beam F8 generated throughthe divided region 51 h turns into obliquely linearly polarized lighthaving the polarization direction along the oblique direction resultingfrom +225° rotation of the Y-direction as the beam F4 opposed theretowith the optical axis AX in between does.

In this manner, the annular light intensity distribution 21 is formed ina circumferentially polarized state of the eight equal division type onthe illumination pupil just behind the polarization converting member5A. In the circumferentially polarized state, a beam passing through theannular light intensity distribution 21 is in a linearly polarized statewith the polarization direction along a tangent direction to a circlecentered on the optical axis AX. As a result, if influence ofretardation described below can be ignored, an annular light intensitydistribution will be formed in an almost continuous, circumferentiallypolarized state corresponding to the annular light intensitydistribution 21, on the illumination pupil just behind the micro fly'seye lens 8. Furthermore, an annular light intensity distribution is alsoformed in an almost continuous, circumferentially polarized statecorresponding to the annular light intensity distribution 21, at thepositions of the other illumination pupils optically conjugate with theillumination pupil just behind the micro fly's eye lens 8, i.e., at thepupil position of the imaging optical system 12 and the pupil positionof the projection optical system PL (the position where the aperturestop AS is arranged).

In general, in the case of circumferential polarization illuminationbased on the pupil intensity distribution of the annular shape or themulti-polar shape (dipolar, quadrupolar, octupolar, or other shape) inthe circumferentially polarized state, the light impinging upon thewafer W as a final illumination target surface is in a polarizationstate with a principal component of s-polarized light. The s-polarizedlight herein is linearly polarized light having the polarizationdirection along a direction perpendicular to the plane of incidence(polarized light with the electric vector vibrating in directionsperpendicular to the plane of incidence). The plane of incidence isdefined as follows: when light arrives at a boundary surface of a medium(illumination target surface: the surface of the wafer W), a planeincluding a normal to the boundary surface at that point and a directionof incidence of the light is defined as plane of incidence. As aconsequence, the circumferential polarization illumination improves theoptical performance (the depth of focus and others) of the projectionoptical system and allows the mask pattern image to be formed with highcontrast on the wafer (photosensitive substrate).

In the present embodiment, the desired circumferentially polarized stateas shown in FIG. 5 is generated on the illumination pupil just behindthe polarization converting member 5A. However, if the illuminationoptical system is configured without the phase modulating member 5B inthe present embodiment, the light will not be focused in the requiredcircumferentially polarized state on the wafer W because of influence ofretardation (a phenomenon of occurrence of a phase difference between apair of linear polarization components with their polarizationdirections perpendicular to each other) caused by the subsequent opticalsystem (optical system arranged between the polarization convertingmember 5A and the wafer W) arranged in the optical path downstream thepolarization converting member 5A, and, in turn, it will becomedifficult to form the pattern image of the mask M with required contraston the wafer W.

Referring to FIG. 1, the subsequent optical system (5B-PL) is providedwith a pair of plane reflecting mirrors 120 a, 120 b for bending ofoptical path (path bending mirrors having their respective planarreflecting surfaces) in the optical path of the imaging optical system12. A certain type of projection optical system PL is provided with aplane reflecting mirror in the optical path between the object plane(plane where the pattern surface of the mask M is arranged) and theaperture stop AS. If the illumination optical system is not providedwith the phase modulating member 5B, even if the pupil intensitydistribution 21 is generated in the desired circumferentially polarizedstate on the illumination pupil just behind the polarization convertingmember 5A, as shown in FIG. 6, a pupil intensity distribution 61 will begenerated in a partially disordered polarization state from the desiredcircumferentially polarized state, at the pupil position (the positionof the illumination pupil: the position where the aperture stop AS isarranged) in the optical path of the projection optical system PLbecause of the influence of the retardation caused by these planereflecting mirrors.

Specifically, in the pupil intensity distribution 21, beams 21 a, 21 bof vertically polarized light and laterally polarized light having thepolarization directions along the directions corresponding to thepolarization direction of p-polarized light or the polarizationdirection of s-polarized light relative to the reflecting surfaces ofthe plane reflecting mirrors are rarely affected by the retardation bythe plane reflecting mirrors and turn into beams 61 a, 61 b ofvertically polarized light and laterally polarized light in the pupilintensity distribution 61. However, beams 21 c of obliquely polarizedlight having the polarization directions along directions obliquelyintersecting with the directions corresponding to the polarizationdirection of p-polarized light or the polarization direction ofs-polarized light are affected by the retardation by the planereflecting mirrors and turn into beams 61 c of elliptically polarizedlight (which is a general concept including circularly polarized light)in the pupil intensity distribution 61.

In the present embodiment, the phase modulating member 5B is providedjust behind the polarization converting member 5A, in order to make thepolarization state of the pupil intensity distribution formed on theillumination pupil in the optical path of the projection optical systemPL, closer to the desired circumferentially polarized state against theretardation caused by the subsequent optical system. The phasemodulating member 5B is a wave plate extending across the entire crosssection of the illumination optical path and having uniform thickness,as shown in FIG. 7, and its optic axis 52 is set in the Y-direction (orX-direction). In other words, the optic axis 52 of the wave plateforming the phase modulating member 5B is set in the directioncorresponding to the polarization direction of p-polarized light or thepolarization direction of s-polarized light relative to the reflectingsurfaces of the plane reflecting mirrors in the subsequent opticalsystem.

In this case, as shown in FIG. 8, the beams 21 a, 21 b of verticallypolarized light and laterally polarized light in the pupil intensitydistribution 21 just behind the polarization converting member 5A arerarely subjected to phase modulation by the phase modulating member 5Band turn into beams 31 a, 31 b of vertically polarized light andlaterally polarized light in a light intensity distribution 31 formedjust behind the phase modulating member 5B. On the other hand, beams 21c of obliquely polarized light are subjected to phase modulation by thephase modulating member 5B and turn into beams 31 c of ellipticallypolarized light in the light intensity distribution 31. The degree ofpolarization of the beams 31 c of elliptically polarized light isdependent upon the thickness of the wave plate forming the phasemodulating member 5B.

FIG. 1 shows the example in which the subsequent optical system has thetwo planar reflecting surfaces (corresponding to the reflecting surfacesof the plane reflecting mirrors 120 a, 120 b for bending of opticalpath), but the subsequent optical system may have only one planarreflecting surface. For example, in a case where a reflecting surface iscomposed of a plane reflecting mirror as in the example of FIG. 1, asingle reflecting mirror for bending of optical path can be provided inthe optical path of the imaging optical system 12. The optic axis of thewave plate forming the phase modulating member 5B is set in a directionalong a first plane including the optical axis of the optical systemarranged on the light source side of the reflecting mirror for bendingof optical path and the optical axis of the optical system arranged onthe illumination target surface side of the reflecting mirror forbending of optical path, or in a direction perpendicular to thedirection along the first plane. In this case, the wave plate formingthe phase modulating member transmits the light from the pupil intensitydistribution so as to convert linearly polarized light thereof polarizedin a first direction, into required elliptically polarized light andmaintain the polarization state of linearly polarized light polarized ina second direction obliquely intersecting with the first direction. Thesecond direction corresponds to the polarization direction ofp-polarized light or the polarization direction of s-polarized lightrelative to the reflecting surface.

The subsequent optical system may have a plurality of planar reflectingsurfaces (two, three, four, or more reflecting surfaces). Namely, wherethe reflecting surfaces are composed of plane reflecting mirrors, aconfiguration obtained by providing the foregoing configuration whereinthe single reflecting mirror for bending of optical path is provided inthe optical path of the imaging optical system 12, with anotherreflecting mirror for bending of optical path, corresponds to theexample shown in FIG. 1. In this case, a second plane including theoptical axis of the optical system arranged on the light source side ofthe other reflecting mirror for bending of optical path and the opticalaxis of the optical system arranged on the illumination target surfaceside of the other reflecting mirror for bending of optical path iscoincident with the first plane or parallel to the first plane.Furthermore, in the cases where the subsequent optical system has aplurality of reflecting surfaces, the second direction also correspondsto the polarization direction of p-polarized light or the polarizationdirection of s-polarized light relative to each of the reflectingsurfaces.

In the light intensity distribution 31 just behind the phase modulatingmember 5B, the beams 31 a, 31 b of vertically polarized light andlaterally polarized light are rarely affected by the retardation by thesubsequent optical system (among others, the retardation by the planarreflecting surfaces provided in the optical path of the subsequentoptical system) and turn into beams 41 a, 41 b of vertically polarizedlight and laterally polarized light in a pupil intensity distribution 41formed on the illumination pupil in the optical path of the projectionoptical system PL. Furthermore, the beams 31 c of elliptically polarizedlight in the light intensity distribution 31 are affected by theretardation by the subsequent optical system and turn into beams 41 c ofalmost required obliquely polarized light in the pupil intensitydistribution 41.

In the present embodiment, the polarization converting member 5Aconverts the polarization state of incident light to form the pupilintensity distribution 21 in the circumferentially polarized state onthe illumination pupil just behind it. The phase modulating member 5Bcomposed of the wave plate arranged just behind the polarizationconverting member 5A transmits the light from the pupil intensitydistribution 21 so as to convert the beams 21 c of obliquely polarizedlight polarized in oblique directions (directions intersecting at 45°with the X-direction and the Y-direction), into the beams 31 c ofrequired elliptically polarized light and maintain the polarizationstates of the beams 21 a, 21 b of vertically polarized light andlaterally polarized light polarized in the Y-direction and X-direction.

The degree of polarization of the beams 31 c subjected to the phasemodulation from obliquely polarized light into elliptically polarizedlight by the phase modulating member 5B (and, therefore, the thicknessof the wave plate forming the phase modulating member 5B) is set in sucha manner that the beams 31 c of elliptically polarized light turn intothe beams 41 c of almost required obliquely polarized light in the pupilintensity distribution 41, after affected by the retardation by thesubsequent optical system. As a result, the influence of retardation isreduced by the phase modulation action of the phase modulating member5B, whereby the pupil intensity distribution 41 is generated in thealmost desired, circumferentially polarized state on the illuminationpupil in the optical path of the projection optical system PL.

As described above, the illumination optical system (1-12) of thepresent embodiment reduces the influence of the retardation caused bythe subsequent optical system behind the polarization converting member5A and is able to illuminate the pattern surface of the mask M as anillumination target surface with the light in the requiredcircumferentially polarized state. Furthermore, the exposure apparatus(1-WS) of the present embodiment is able to image the pattern of themask M with required contrast on the wafer W, using the illuminationoptical system (1-12) which illuminates the pattern of the mask M withthe light in the required circumferentially polarized state.

The above description concerned the incidence of the Y-directionallylinearly polarized light into the polarization converting member 5A, butif X-directionally linearly polarized light is incident thereinto, anannular light intensity distribution 22 is formed in a substantiallycontinuous, radially polarized state of the eight equal division type,as shown in FIG. 9, on the illumination pupil just behind thepolarization converting member 5A. As a result, if the influence ofretardation can be ignored, the annular light intensity distributionwill also be formed in the substantially continuous, radially polarizedstate corresponding to the annular light intensity distribution 22, onthe illumination pupil just behind the micro fly's eye lens 8, at thepupil position of the imaging optical system 12, and at the pupilposition of the projection optical system PL.

In general, in the case of the radial polarization illumination based onthe pupil intensity distribution of the annular shape or the multi-polarshape in the radially polarized state, the light impinging upon thewafer W as a final illumination target surface is in a polarizationstate with a principal component of p-polarized light. The p-polarizedlight herein is linearly polarized light having the polarizationdirection along a direction parallel to the plane of incidence definedas described above (or polarized light with the electric vectorvibrating in directions parallel to the plane of incidence). As aresult, the radial polarization illumination reduces the reflectance oflight on a resist applied onto the wafer W, and allows a good maskpattern image to be formed on the wafer W.

It is, however, often the case in practice that the influence ofretardation caused by the subsequent optical system cannot be ignored.In that case, where the illumination optical system is configuredwithout the phase modulating member 5B, beams 22 c of obliquelypolarized light in the pupil intensity distribution 22 are affected bythe retardation and turn into beams 62 c of elliptically polarized lightin a pupil intensity distribution 62 formed on the illumination pupil inthe optical path of the projection optical system PL. Beams 22 a, 22 bof vertically polarized light and laterally polarized light are rarelyaffected by the retardation and turn into beams 61 a, 61 b of verticallypolarized light and laterally polarized light in the pupil intensitydistribution 62.

In the present embodiment, in the case of the radial polarizationillumination, the beams 22 a, 22 b of vertically polarized light andlaterally polarized light in the pupil intensity distribution 22 justbehind the polarization converting member 5A are rarely affected by thephase modulation by the phase modulating member 5B and the retardationby the subsequent optical system and turn into the beams of verticallypolarized light and laterally polarized light in the pupil intensitydistribution formed on the illumination pupil in the optical path of theprojection optical system PL. On the other hand, the beams 22 c ofobliquely polarized light are subject to the phase modulation by thephase modulating member 5B and turn into elliptically polarized light,and thereafter the elliptically polarized beams are affected by theretardation by the subsequent optical system and return into the almostrequired obliquely polarized beams. As a result, the influence ofretardation is reduced by the phase modulation action of the phasemodulating member 5B and the pupil intensity distribution is generatedin the almost desired, radially polarized state on the illuminationpupil in the optical path of the projection optical system PL.

The above description explained the operational effect of the presentembodiment, using the modified illumination in which the annular pupilintensity distribution is formed on the illumination pupil, i.e., theannular illumination as an example. It is, however, clear that, withouthaving to be limited to the annular illumination, the present embodimentcan be similarly applied, for example, to the multi-polar illuminationin which a multi-polar pupil intensity distribution is formed, and otherillumination to achieve the same operational effect.

As an example, as shown in FIG. 11, where an octupolar light intensitydistribution 23 is formed in a circumferentially polarized state on theillumination pupil just behind the polarization converting member 5Athrough the use of a diffraction optical element for octupolarillumination, an octupolar pupil intensity distribution can also begenerated in an almost desired, circumferentially polarized state on theillumination pupil in the optical path of the projection optical systemPL by the phase modulation action of the phase modulating member 5B. Ina case where an octupolar light intensity distribution 24 is formed in aradially polarized state on the illumination pupil just behind thepolarization converting member 5A as shown in FIG. 12, an octupolarpupil intensity distribution can also be generated in an almost desired,radially polarized state on the illumination pupil in the optical pathof the projection optical system PL by the phase modulation action ofthe phase modulating member 5B.

Incidentally, the annular or octupolar pupil intensity distribution21-24 includes the mixture of the beams 21 a-24 a; 21 b-24 b ofvertically polarized light and laterally polarized light with the beams21 c-24 c of obliquely polarized light. Therefore, the beams 21 a-24 a;21 b-24 b of vertically polarized light and laterally polarized lightare kept as vertically polarized light and laterally polarized lightrarely affected by the phase modulation by the phase modulating member5B and the beams 21 c-24 c of obliquely polarized light turn into theelliptically polarized light as subjected to the phase modulation by thephase modulating member 5B.

In contrast to it, in a case where an X-shaped quadrupolar lightintensity distribution 25 is formed in a circumferentially polarizedstate on the illumination pupil just behind the polarization convertingmember 5A through the use of a diffraction optical element forquadrupolar illumination as shown in FIG. 13, there are only beams 25 aof first obliquely polarized light and beams 25 b of second obliquelypolarized light in a light intensity distribution 25, and there are nobeams of vertically polarized light and laterally polarized light.Therefore, the beams 25 a of first obliquely polarized light and thebeams 25 b of second obliquely polarized light are subjected to thephase modulation by the phase modulating member 5B to turn intoelliptically polarized light beams, and thereafter the ellipticallypolarized light beams are affected by the retardation by the subsequentoptical system to return into substantially required, first obliquelypolarized light and second obliquely polarized light.

Similarly, in a case where an X-shaped quadrupolar light intensitydistribution 26 is formed in a radially polarized state on theillumination pupil just behind the polarization converting member 5A asshown in FIG. 14, there are only beams 26 a of first obliquely polarizedlight and beams 26 b of second obliquely polarized light in a lightintensity distribution 26, and there are no beams of verticallypolarized light and laterally polarized light. Therefore, the beams 26 aof first obliquely polarized light and the beams 26 b of secondobliquely polarized light are subjected to the phase modulation by thephase modulating member 5B to turn into elliptically polarized beams andthereafter the elliptically polarized beams are affected by theretardation by the subsequent optical system to return into almostrequired, first obliquely polarized light and second obliquely polarizedlight.

The above-described embodiment explained the embodiment of the presentinvention on the basis of the polarization converting member 5A havingthe specific configuration shown in FIG. 3. However, without having tobe limited to this, the configuration of the polarization convertingmember can be modified in various forms. Specifically, a variety offorms can be contemplated as to the arrangement position, material,structure (the contour, the number of division, the surface shape(thickness distribution), and the side where the uneven surface isformed), etc. of the polarization converting member.

For example, in the foregoing embodiment the polarization convertingmember 5A is arranged at or near the pupil position of the afocal lens4. However, without having to be limited to this, the polarizationconverting member 5A can be arranged at the position of the otherillumination pupil or a position near it in the illumination opticalsystem (1-12). Specifically, the polarization converting member 5A canalso be arranged near the entrance plane of the micro fly's eye lens 8,near the exit plane of the micro fly's eye lens 8, at or near the pupilposition of the imaging optical system 12, and so on.

In the above-described embodiment, the polarization converting member 5Ahas the contour of circular shape in whole and is divided into the eightarcuate regions 51 a-51 h. However, without having to be limited tothis, a variety of forms can be contemplated as to the overall contour,the number of division, etc. of the polarization converting member.

In the above-described embodiment, the polarization converting member 5Ais made of rock crystal. However, the material does not always have tobe limited to rock crystal, but the polarization converting member mayalso be made of another appropriate optical material having an opticalrotatory power. Furthermore, the member does not always have to belimited to the optically rotatory member, but the polarizationconverting member can also be configured using a plurality of waveplates that change incident light into light in a predeterminedpolarization state.

In the aforementioned embodiment, the phase modulating member 5B iscomposed of the wave plate having the uniform thickness, and is arrangedat the position just behind the polarization converting member 5A, i.e.,at the illumination pupil or at the position near it. However, withouthaving to be limited to this, a variety of forms can be contemplated asto the specific configuration, the arrangement position, etc. of thephase modulating member. For example, the phase modulating member 5B canbe arranged at an appropriate position in the optical path behind thepolarization converting member 5A (on the mask M side thereof), i.e., atan appropriate position in the optical path downstream the illuminationpupil. However, when the phase modulating member 5B is arranged at theillumination pupil or at the position near it, it becomes feasible tomake uniform phase modulation act on the illumination pupil plane.

In general, the phase modulating member functions to transmit light soas to convert obliquely polarized light in the pupil intensitydistribution formed on the illumination pupil through the polarizationconverting member, into required elliptically polarized light andmaintain the polarization state of vertically polarized light orlaterally polarized light in the pupil intensity distribution. It isimportant herein that the degree of polarization of light subjected tothe phase modulation from obliquely polarized light into ellipticallypolarized light by the phase modulating member be set so that theelliptically polarized light becomes closer to required obliquelypolarized light after affected by the retardation by the subsequentoptical system behind the polarization converting member.

In the aforementioned embodiment the phase modulating member 5B isarranged just behind the polarization converting member 5A. In thiscase, if necessary, the polarization converting member 5A and the phasemodulating member 5B can be integrally held and configured so as to beintegrally inserted into or retracted from the illumination opticalpath. The polarization converting member and the phase modulating membermay also be configured each so as to be inserted into or retracted fromthe illumination optical path and so as to be positioned in theillumination optical path as occasion may demand.

In the foregoing embodiment, the micro fly's eye lens 8 is used as anoptical integrator, but instead thereof, an optical integrator of aninternal reflection type (typically, a rod type integrator) may also beused. In this case, a condensing lens is arranged behind the zoom lens 7so that its front focal position coincides with the rear focal positionof the zoom lens 7, and the rod type integrator is arranged so that anentrance end thereof is positioned at or near the rear focal position ofthis condensing lens. In this case, an exit end of the rod typeintegrator is located at the position of the illumination field stop 11.When the rod type integrator is used, a position optically conjugatewith the position of the aperture stop of the projection optical systemPL in the field stop imaging optical system 12 downstream this rod typeintegrator can be called an illumination pupil plane. A virtual image ofthe secondary light source on the illumination pupil plane is formed atthe position of the entrance plane of the rod type integrator and,therefore, this position and positions optically conjugate with thisposition can also be called illumination pupil planes.

The exposure apparatus of the above embodiment is manufactured byassembling various sub-systems including the constituent elementsdescribed in the scope of claims in the present application so as tomaintain predetermined mechanical accuracy, electrical accuracy, andoptical accuracy. In order to ensure these various accuracies, thefollowing adjustments are carried out before and after this assembling:adjustment for achieving the optical accuracy for various opticalsystems; adjustment for achieving the mechanical accuracy for variousmechanical systems; adjustment for achieving the electrical accuracy forvarious electrical systems. Assembling blocks from the varioussub-systems into the exposure apparatus include mechanical connection,wiring connection of electric circuits, pipe connection of pneumaticcircuits, etc. between the various sub-systems. It is needless tomention that there are assembling blocks of the individual sub-systems,prior to the assembling blocks from these various sub-systems into theexposure apparatus. After completion of the assembling blocks of thevarious sub-systems into the exposure apparatus, overall adjustment iscarried out so as to ensure the various accuracies as a whole of theexposure apparatus. The manufacture of the exposure apparatus may becarried out in a clean room in which the temperature, cleanliness, etc.are controlled.

The below will describe a device manufacturing method using the exposureapparatus of the above embodiment. FIG. 15 is an exemplary flowchartshowing manufacturing blocks of semiconductor devices. As shown in FIG.15, the manufacturing blocks of semiconductor devices includeevaporating a metal film on a wafer W as a substrate for semiconductordevices (block S40), and applying a photoresist as a photosensitivematerial onto the evaporated metal film (block S42). Subsequently, usingthe exposure apparatus of the above embodiment, a pattern formed on amask (reticle) M is transferred into each shot area on the wafer W(block S44: exposure block) and the block thereafter is to develop thewafer W after completion of the transfer, i.e., develop the photoresiston which the pattern is transferred (block S46: development block).Thereafter, using the resist pattern formed on the surface of the waferW in block S46, as a mask, the surface of the wafer W is subjected toprocessing such as etching (block S48: processing block).

The resist pattern herein is a photoresist layer in which projectionsand depressions are formed in a shape corresponding to the patterntransferred by the exposure apparatus of the embodiment and throughwhich the depressions penetrate. Block S48 is to process the surface ofthe wafer W through this resist pattern. The processing carried out inblock S48 includes, for example, at least one of etching of the surfaceof the wafer W and film formation of a metal film or the like. In blockS44, the exposure apparatus of the above embodiment performs thetransfer of the pattern using the wafer W coated with the photoresist,as a photosensitive substrate or plate P.

FIG. 16 is an exemplary flowchart showing manufacturing blocks of aliquid crystal device such as a liquid crystal display device. As shownin FIG. 16, the manufacturing blocks of liquid crystal device are tosequentially carry out a pattern forming block (block S50), a colorfilter forming block (block S52), a cell assembling block (block S54),and a module assembling block (block S56). In the pattern forming blockof block S50, a predetermined pattern such as a circuit pattern and anelectrode pattern is formed on a glass substrate coated with aphotoresist as a plate P, using the exposure apparatus of the aboveembodiment. This pattern forming block includes an exposure block oftransferring the pattern onto the photoresist layer, using the exposureapparatus of the above embodiment, a development block of developing theplate P on which the pattern is transferred, i.e., developing thephotoresist on the glass substrate to generate a photoresist layer in ashape corresponding to the pattern, and a processing block of processingthe surface of the glass substrate through the developed photoresistlayer.

In the color filter forming block of block S52, a color filter is formedin a structure in which a large number of sets of three dotscorresponding to R (Red), G (Green), and B (Blue) are arrayed in amatrix pattern or in a structure in which a plurality of filter sets ofthree stripes of R, G, and B are arrayed in a horizontal scanningdirection. In the cell assembling block of block S54, a liquid crystalpanel (liquid crystal cell) is assembled using the glass substrate withthe predetermined pattern formed in block S50, and the color filterformed in block S52. Specifically, for example, a liquid crystal ispoured into between the glass substrate and the color filter to form theliquid crystal panel. In the module assembling block of block S56,various components such as an electric circuit and backlights fordisplay operation of this liquid crystal panel are attached to theliquid crystal panel assembled in block S54.

The present embodiment is not limited to the application to the exposureapparatus for manufacture of semiconductor devices, but can also bewidely applied to exposure apparatus for display devices such as liquidcrystal display devices or plasma displays formed with rectangular glassplates, and to exposure apparatus for manufacture of various devicessuch as imaging devices (CCD and others), micromachines, thin filmmagnetic heads, and DNA chips. Furthermore, the present embodiment canalso be applied to an exposure block (exposure apparatus) inmanufacturing masks (photomasks, reticles, etc.) on which mask patternsfor various devices are formed, by the photolithography process.

The above embodiment used the ArF excimer laser light (wavelength: 193nm) or the KrF excimer laser light (wavelength: 248 nm) as the exposurelight, but, without having to be limited to this, it is also possible toapply the present embodiment to other appropriate laser light sources,e.g., an F₂ laser light source to supply laser light at the wavelengthof 157 nm.

The projection optical system in the above embodiment does not alwayshave to be limited to the reduction system but may be either of an equalmagnification system or an enlargement system; the projection opticalsystem does not have to be limited to the dioptric system only, but maybe any of catoptric and catadioptric systems; the projection imagethereof may be either of an inverted image and an erect image.

In the foregoing embodiment, it is also possible to apply a technique offilling the interior space of the optical path between the projectionoptical system and the photosensitive substrate with a medium having therefractive index of more than 1.1 (typically, a liquid), the so-calledliquid immersion method. In this case, the technique of filling theinterior space of the optical path between the projection optical systemand the photosensitive substrate with the liquid can be one selectedfrom the technique of locally filling the space with the liquid asdisclosed in International Publication WO99/49504, the technique ofmoving a stage holding a substrate as an object to be exposed, in aliquid bath as disclosed in Japanese Patent Application Laid-Open No.H6-124873, the technique of forming a liquid bath in a predetermineddepth on a stage and holding the substrate therein as disclosed inJapanese Patent Application Laid-Open No. H10-303114, and so on. Theteachings of International Publication WO99/49504, Japanese PatentApplication Laid-Open No. H6-124873, and Japanese Patent ApplicationLaid-Open No. H10-303114 above are incorporated herein by reference.

In the foregoing embodiment, instead of the diffraction optical element3 or in addition to the diffraction optical element 3, it is alsopossible to use, for example, a spatial light modulating element whichis composed of a large number of microscopic element mirrors arranged inan array form and individually driven and controlled in their angle anddirection of inclination and which divides an incident beam intomicroscopic units of respective reflecting faces so as to deflectdivided beams, thereby converting the cross section of the beam into adesired shape or a desired size. The illumination optical system usingsuch a spatial light modulating element is disclosed, for example, inJapanese Patent Application Laid-Open No. 2002-353105.

When such a spatial light modulator is used, the polarization convertingmember configured to convert the polarization state of incident light toform the pupil intensity distribution in the predetermined polarizationstate on the illumination pupil of the illumination optical system maybe arranged so that it can be located in the illumination optical pathon the light source side of the spatial light modulator.

In the above embodiment, a variable pattern forming device to form apredetermined pattern on the basis of predetermined electronic data canbe used instead of the mask. The variable pattern forming deviceapplicable herein can be, for example, a spatial light modulatingelement including a plurality of reflecting elements driven based on thepredetermined electronic data. The exposure apparatus using the spatiallight modulating element is disclosed, for example, in Japanese PatentApplication Laid-Open No. 2004-304135 and U.S. Patent ApplicationLaid-Open No. 2007/0296936. Besides the reflection type spatial lightmodulators of the non-emission type as described above, it is alsopossible to use a transmission type spatial light modulator or aself-emission type image display device.

The above embodiment was the embodiment of the present invention appliedto the illumination optical system for illuminating the mask (or thewafer) in the exposure apparatus, but, without having to be limited tothis, it is also possible to apply the present embodiment to the generalillumination optical systems for illuminating the illumination targetsurface except for the mask (or the wafer).

It will be understood by those skilled in the art that aspects ofembodiments of the subject matter disclosed above are intended tosatisfy the requirement of disclosing at least one enabling embodimentof the subject matter of each claim and to be one or more such exemplaryembodiments only and to not to limit the scope of any of the claims inany way and particularly not to a specific disclosed embodiment alone.Many changes and modification can be made to the disclosed aspects ofembodiments of the disclosed subject matter of the claims that will beunderstood and appreciated by those skilled in the art, particularly inregard to interpretation of the claims for purposes of the doctrine ofequivalents. The appended claims are intended in scope and meaning tocover not only the disclosed aspects of embodiments of the claimedsubject matter but also such equivalents and other modifications andchanges that would be apparent to those skilled in the art. In additionsto changes and modifications to the disclosed and claimed aspects of thesubject matter disclosed of the disclosed subject matter(s) noted above,others could be implemented.

While the particular aspects of embodiment(s) of the {TITLE} describedand illustrated in this patent application in the detail required tosatisfy 35 U.S.C. § 112 is fully capable of attaining anyabove-described purposes for, problems to be solved by or any otherreasons for or objects of the aspects of an embodiment(s) abovedescribed, it is to be understood by those skilled in the art that it isthe presently described aspects of the described embodiment(s) of thesubject matter claimed are merely exemplary, illustrative andrepresentative of the subject matter which is broadly contemplated bythe claimed subject matter. The scope of the presently described andclaimed aspects of embodiments fully encompasses other embodiments whichmay now be or may become obvious to those skilled in the art based onthe teachings of the Specification. The scope of the present {TITLE} issolely and completely limited by only the appended claims and nothingbeyond the recitations of the appended claims. Reference to an elementin such claims in the singular is not intended to mean nor shall it meanin interpreting such claim element “one and only one” unless explicitlyso stated, but rather “one or more”. All structural and functionalequivalents to any of the elements of the above-described aspects of anembodiment(s) that are known or later come to be known to those ofordinary skill in the art are expressly incorporated herein by referenceand are intended to be encompassed by the present claims. Any term usedin the Specification and/or in the claims and expressly given a meaningin the Specification and/or claims in the present application shall havethat meaning, regardless of any dictionary or other commonly usedmeaning for such a term. It is not intended or necessary for a device ormethod discussed in the Specification as any aspect of an embodiment toaddress each and every problem sought to be solved by the aspects ofembodiments disclosed in this application, for it to be encompassed bythe present claims. No element, component, or method step in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element, component, or method step is explicitly recited inthe claims. No claim element in the appended claims is to be construedunder the provisions of 35 U.S.C. § 112, sixth paragraph, unless theelement is expressly recited using the phrase “means for” or, in thecase of a method claim, the element is recited as a “step” instead of an“act.”

It will be understood also be those skilled in the art that, infulfillment of the patent statutes of the United States, Applicant(s)has disclosed at least one enabling and working embodiment of eachinvention recited in any respective claim appended to the Specificationin the present application and perhaps in some cases only one. Forpurposes of cutting down on patent application length and drafting timeand making the present patent application more readable to theinventor(s) and others, Applicant(s) has used from time to time orthroughout the present application definitive verbs (e.g., “is”, “are”,“does”, “has”, “includes” or the like) and/or other definitive verbs(e.g., “produces,” “causes” “samples,” “reads,” “signals” or the like)and/or gerunds (e.g., “producing,” “using,” “taking,” “keeping,”“making,” “determining,” “measuring,” “calculating” or the like), indefining an aspect/feature/element of, an action of or functionality of,and/or describing any other definition of an aspect/feature/element ofan embodiment of the subject matter being disclosed. Wherever any suchdefinitive word or phrase or the like is used to describe anaspect/feature/element of any of the one or more embodiments disclosedherein, i.e., any feature, element, system, sub-system, component,sub-component, process or algorithm step, particular material, or thelike, it should be read, for purposes of interpreting the scope of thesubject matter of what applicant(s) has invented, and claimed, to bepreceded by one or more, or all, of the following limiting phrases, “byway of example,” “for example,” “as an example,” “illustratively only,”“by way of illustration only,” etc., and/or to include any one or more,or all, of the phrases “may be,” “can be”, “might be,” “could be” andthe like. All such features, elements, steps, materials and the likeshould be considered to be described only as a possible aspect of theone or more disclosed embodiments and not as the sole possibleimplementation of any one or more aspects/features/elements of anyembodiments and/or the sole possible embodiment of the subject matter ofwhat is claimed, even if, in fulfillment of the requirements of thepatent statutes, Applicant(s) has disclosed only a single enablingexample of any such aspect/feature/element of an embodiment or of anyembodiment of the subject matter of what is claimed. Unless expresslyand specifically so stated in the present application or the prosecutionof this application, that Applicant(s) believes that a particularaspect/feature/element of any disclosed embodiment or any particulardisclosed embodiment of the subject matter of what is claimed, amountsto the one an only way to implement the subject matter of what isclaimed or any aspect/feature/element recited in any such claim,Applicant(s) does not intend that any description of any disclosedaspect/feature/element of any disclosed embodiment of the subject matterof what is claimed in the present patent application or the entireembodiment shall be interpreted to be such one and only way to implementthe subject matter of what is claimed or any aspect/feature/elementthereof, and to thus limit any claim which is broad enough to cover anysuch disclosed implementation along with other possible implementationsof the subject matter of what is claimed, to such disclosedaspect/feature/element of such disclosed embodiment or such disclosedembodiment. Applicant(s) specifically, expressly and unequivocallyintends that any claim that has depending from it a dependent claim withany further detail of any aspect/feature/element, step, or the like ofthe subject matter of what is claimed recited in the parent claim orclaims from which it directly or indirectly depends, shall beinterpreted to mean that the recitation in the parent claim(s) was broadenough to cover the further detail in the dependent claim along withother implementations and that the further detail was not the only wayto implement the aspect/feature/element claimed in any such parentclaim(s), and thus be limited to the further detail of any suchaspect/feature/element recited in any such dependent claim to in any waylimit the scope of the broader aspect/feature/element of any such parentclaim, including by incorporating the further detail of the dependentclaim into the parent claim.

1-16. (canceled)
 17. An illumination optical system which illuminates anillumination target surface with illumination light, comprising: anoptical rotatory member arranged on an optical path of the illuminationlight and comprised of a material having an optical rotatory power; anda phase member, on the optical path of the illumination light, arrangedbetween the optical rotatory member and the illumination target surface,the phase member configured to emit the illumination light whileproviding a phase difference between polarization components in theillumination light, polarization directions of the polarizationcomponents in the illumination light being orthogonal to each other. 18.The illumination optical system according to claim 17, wherein theoptical rotatory member receives a first linearly polarized light havinga polarization direction along a first direction, and the opticalrotatory member emits a second linearly polarized light having apolarization direction along a second direction different from the firstdirection.
 19. The illumination optical system according to claim 18,wherein the phase member emits the second linearly polarized light fromthe optical rotatory member while providing a phase difference betweenpolarization components in the second linearly polarized light,polarization directions of the polarization components in the secondlinearly polarized light being orthogonal to each other.
 20. Theillumination optical system according to claim 18, wherein the opticalrotatory member emits a third linearly polarized light having apolarization direction along a third direction different from the seconddirection.
 21. The illumination optical system according to claim 20,wherein the phase member emits the second linearly polarized light whileproviding a phase difference between polarization components in thesecond linearly polarized light and emits the third linearly polarizedlight, polarization directions of the components in second linearlypolarized light being orthogonal to each.
 22. The illumination opticalsystem according to claim 21, wherein the illumination optical systemincludes a reflecting surface arranged on the optical path of theillumination light and reflecting the illumination light, and the thirddirection is a polarization direction serving as s-polarization orp-polarization with respect to the reflecting surface.
 23. Theillumination optical system according to claim 20, wherein theillumination optical system includes a distribution forming memberarranged on the optical path of the illumination light and distributingthe illumination light on a pupil surface of the illumination opticalsystem.
 24. The illumination optical system according to claim 23,wherein light from the phase member, including the polarizationcomponents orthogonal to each other and provided with the phasedifference by the phase member, and the third linearly polarized lightfrom the phase member pass through difference positions on the pupilsurface respectively.
 25. The illumination optical system according toclaim 18, wherein the illumination optical system includes a reflectingsurface arranged on the optical path of the illumination light andreflecting the illumination light, and the second direction is differentfrom a polarization direction serving as s-polarization orp-polarization with respect to the reflecting surface.
 26. Theillumination optical system according to claim 17, wherein the opticalrotatory member includes a crystal optical member having an optical axispositioned in a direction along the optical axis of the illuminationoptical system or in a direction parallel to the optical axis of theillumination optical system.
 27. The illumination optical systemaccording to claim 26, wherein the phase member includes a crystaloptical member having an optical axis positioned in a directionintersecting the optical axis of the illumination optical system.
 28. Anillumination optical system which illuminates an illumination targetsurface with illumination light, comprising: a polarization memberarranged on an optical path of the illumination light, the polarizationmember configured to set a polarization state of first illuminationlight serving as first part of the illumination light into first linearpolarization having a polarization direction along a first direction andset a polarization state of second illumination light serving as secondpart of the illumination light into second linear polarization having apolarization direction along a second direction, the second part beingdifferent from the first part, the second direction being different fromthe first direction; a reflecting surface arranged on the optical pathof the illumination light, the reflecting surface configured to reflectthe first illumination light and the second illumination light, thepolarization direction of the first linear polarization serving ass-polarization or p-polarization with respect to the reflecting surface;and a phase member, on the optical path of the illumination light,arranged between the polarization member and the illumination targetsurface, the phase member configured to emit the second illuminationlight while providing a phase difference between polarization componentsin the second illumination light and emit the first illumination lightwhile maintaining the polarization state of the first illumination lightin the first linear polarization, polarization directions of thepolarization components in the second illumination light beingorthogonal to each other.
 29. The illumination optical system accordingto claim 28, wherein the phase difference, caused between thepolarization components in the second illumination light by the phasemember, includes a reversely-oriented phase difference with respect to aphase difference, the reversely-oriented phase difference being causedbetween the polarization components in the second illumination light bythe reflecting surface.
 30. The illumination optical system according toclaim 29, wherein the polarization direction, serving as thes-polarization or the p-polarization with respect to the reflectingsurface, is excluded from the polarization direction of the secondlinear polarization.
 31. The illumination optical system according toclaim 29, wherein the first direction and the second direction are setin a positional relationship that excludes a relationship in which thefirst direction and the second direction are orthogonal to each other.32. The illumination optical system according to claim 29, wherein thephase member includes a wave plate having an optical axis directed in adirection intersecting the optical path of the illumination light. 33.The illumination optical system according to claim 32, wherein theoptical axis of the wave plate is directed in the first direction or adirection orthogonal to the first direction.
 34. The illuminationoptical system according to claim 33, wherein a thickness of the waveplate, in a direction along the optical path of the illumination light,is uniform on a surface intersecting the optical path of theillumination light.
 35. The illumination optical system according toclaim 28, wherein the polarization member is comprised of an opticalmaterial having an optical rotatory power, and the optical rotatorypower causes a difference between the polarization directions of thefirst illumination light and the second illumination light.
 36. Theillumination optical system according to claim 35, wherein thepolarization member is arranged so that an optical axis of the opticalmaterial with the optical rotatory power trends in a direction along anoptical axis of the illumination optical system.
 37. The illuminationoptical system according to claim 36, wherein the polarization member isarranged so that the first illumination light and the secondillumination light, out of the illumination light entering at thepolarization member in a linear polarization state having a polarizationdirection corresponding to a predetermined direction, pass through theoptical material in mutually different lengths along a direction of theoptical axis of the optical material.
 38. An exposure apparatuscomprising the illumination optical system as set forth in claim 17which illuminates a predetermined pattern, the exposure apparatusperforming exposure of a photosensitive substrate with light from thepredetermined pattern.
 39. The exposure apparatus according to claim 38,further comprising: a projection optical system which projects light viathe predetermined pattern onto the photosensitive substrate.
 40. Adevice manufacturing method, comprising: performing exposure of thesubstrate, using the exposure apparatus as set forth in claim 38;developing the photosensitive substrate on which the predeterminedpattern is transferred and forming a mask layer with a shapecorresponding to the predetermined pattern; and processing a surface ofthe photosensitive substrate through the mask layer.
 41. An exposureapparatus comprising the illumination optical system as set forth inclaim 28 which illuminates a predetermined pattern, the exposureapparatus performing exposure of a photosensitive substrate with lightfrom the predetermined pattern.
 42. The exposure apparatus according toclaim 41, further comprising: a projection optical system which projectslight via the predetermined pattern onto the photosensitive substrate.43. A device manufacturing method, comprising: performing exposure ofthe substrate, using the exposure apparatus as set forth in claim 41;developing the photosensitive substrate on which the predeterminedpattern is transferred and forming a mask layer with a shapecorresponding to the predetermined pattern; and processing a surface ofthe photosensitive substrate through the mask layer.